The present invention generally relates to a cooling air circulation system at the front end of a motor vehicle, and more particularly to a system which utilizes the available cross-sectional area at the front end as completely as possible.
A cooling air circulation system at the front end of a motor vehicle is disclosed by German Patent Specification (DE-PS) 33 38 466. In this cooling air circulation system, a lower air duct leads to a water cooler and an upper air duct to a supplementary cooler. This restricts the lower air duct to such an extent that the water cooler, which is acted upon by the cooling air in this lower air duct, at a suitable distance from the end of the front end, can only utilize a part of the height of the front end space.
Accordingly, an object of the present invention is to provide a cooling air circulation system at the front end of a motor vehicle that utilizes the available cross-sectional area at the front end space as completely as possible for the cooling air circulation, with different ventilation possibilities for individual coolers being geared to cooling requirements.
In the cooling air circulation system according to preferred embodiments of the invention, a lower air duct exits into the open in front of a water cooler, and the front end space in the area of the water cooler is occupied to practically its entire height by upper and central air ducts, so that the water cooler which is acted upon by cooling air from these ducts can also extend over this entire height. A condenser connected in front of the upper section of the water cooler is acted upon solely by cooling air, which if necessary is delivered by an electric fan, from the upper air duct, while the cooling air of the central air duct acts solely upon the water cooler, so that adequate cooling of the cooling water is also ensured when there is only inadequate cooling in the upper section of the water cooler as a result of considerable heating up of the cooling air in the condenser.
Sealing of the air ducts with respect of one another and from the outside eliminates cooling air loss by leakage, and sealing of the cooling air flow between the electric fan and the water cooler by the fan cowl prevents a return flow of the cooling air delivered by the electric fan. Both measures render possible optimum utilization of the cooling air, by means of which an improvement of the water cooling and the air-conditioning as well as a smaller design of the cooler surfaces and of the fan drive are achieved.
The one embodiment of the cooling air circulation system wherein an additional fan is arranged down stream from water cooler renders possible cooling of both the water cooler and the condenser independently of the speed of the motor vehicle and of the activity of the electric fan, the space necessary for the fan driven by the internal combustion engine remaining the same, in spite of the increased number of coolers, as a result of the favorable utilization of the space available in the front end.
Due to the advantageous placement of the front bumper with respect to the air inlet ducts, the best possible by-passing of the bumper by the air ducts is achieved. Each air duct can be assigned an inlet surface which corresponds to its cross-section in the cooler area. All the inlet opening lie in the compression area in the wall of the front end, by virtue of which the cooling air delivery is supported.
The advantageous placement of a spoiler at the outlet of the lower air duct increases the low pressure at the outlet opening of the lower air duct, so that the flow through it is ensured without fan support also.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.